[[quoteright:242:http://static.tvtropes.org/pmwiki/pub/images/xenomorph_642.jpg]][[caption-width-right:242: ''In space, no one can hear you scream.'']]

->''"You still don't understand what you're dealing with, do you? A perfect organism. Its structural perfection is matched only by its hostility."''-->-- '''Ash''', ''Film/{{Alien}}'' (1979)

''Alien'' is a Creator/TwentiethCenturyFox multimedia film franchise created by Dan O'Bannon and Ronald Shusett, that [[TropeCodifier codified]] [[SciFiHorror science fiction]] BodyHorror. The franchise, which spans films, novels, comic books, and video games, helped to launch the careers of creators like Creator/RidleyScott, Creator/JamesCameron, and Creator/SigourneyWeaver.

The series revolves around the "Xenomorphs", alien monsters with [[AlienBlood acid blood]] that spawn by [[FaceFullOfAlienWingWong bursting out of other organisms' chests]] and try to [[AlwaysChaoticEvil kill anything that isn't them]]. Most works involve humans encountering the creatures, [[{{Horror}} with horrific results]]. A wide array of {{Crossover}} works with Fox's ''other'' famous science fiction alien monster, the Franchise/{{Predator}}, also exist. For more information on those, see the ''Franchise/AlienVsPredator'' page.

[[folder:A-G]]* ActionGirl: In the Dark Horse post-''Aliens'' comic series, ''Newt'' becomes one hell of an action girl.* AdaptationExpansion: The comic series branches off from the movies after ''Aliens'', and benefits greatly as a result.* AIIsACrapshoot: Bishop in ''Aliens'' and ''Alien 3'' averts this, explained as having stricter safeguards than the one that went against the crew in the first film. But by ''Alien: Resurrection'', androids have been outlawed with orders to "destroy on sight" because some of them started to make "children".* AirVentPassageway: Both humans and aliens make good use of air vents to get around without the other side noticing. The alien in the first film moves around the spaceship using air vents. In the second film, Newt survives by hiding in the air vents, and the Marines make their escape through the same vents. Newt uses them for more aggressive purposes in the Dark Horse adaptation.* AlienBlood: The aliens have highly corrosive acid for blood.* AlienLandmass: Planet LV-426 (aka Acheron) has rocky formations which are rounded at the top into smooth nubs. Offhand, the rocks greatly resemble bones.* AllWebbedUp: This happens to several victims throughout the series. The Xenomorphs use some kind of unexplained organic resin to cocoon people, leaving them as bait for [[FaceFullOfAlienWingWong facehugger]] eggs.* AlwaysChaoticEvil: The Aliens. They seemingly exist for the sole purpose of killing everything on a planet. It is subtly implied that they are indeed intelligent, not just bestial animals, which simply makes them even more terrifying. [[spoiler: If you listen to ''Prometheus'', this is because they were ''designed'' to be weapons. They can't help killing everything in sight that isn't them, it's what they're ''for''.]]* AmbiguousRobots: This series has a whole spectrum of them. Tending toward the organic end, we have the Xenomorphs and on the probably-robotic end, we have the artificial persons. Right square in the middle is the Space Jockey (and by extension, his ship) from the first movie.* AncientConspiracy: Actually a set of company protocols, but it sure resembles a cult searching for an ArtifactOfDoom they think will bring them power. From the 21st Century (possibly before) to the far future. Years, decades, centuries come and go and every time so much as a hint of a sign of a Xenomorph rears its head, they have a team ready to go, with moles, dupes and those they need for the moment all set to go.* AndIMustScream: In the comics, an adult Newt falls in love with a Colonial Marine, who turns out to be an ArtificialHuman with more advanced emotions. He makes a HeroicSacrifice by staying behind on an infested ship to allow her to escape, but this leaves him trapped on a GhostShip (they leave him alone because he's useless to them for breeding) that can never return to civilization because of the risk.* AppropriatedTitle: Although the third, fourth, and fifth films all went under the original title, most spin-off merchandise is known under ''Alien'''s''''', which was the second movie.* ArtificialHuman: Ash, Bishop and Call (a bit of franchise-wide ThemeNaming which ''Prometheus'' appears to have continued with David). Ash from the first movie [[spoiler:is a particularly sinister example, since he secretly protects the alien and betrays the other crew members.]]* ArtMajorBiology: The Alien's life cycle.** The alien grows from a chestburster to a full-grown adult without apparently eating anything (or anyone) in the first film. This is explained in the original script when the crew corner the chestbuster in a supply closet filled with their food supply and lock it in while they try to find a way to deal with it. When they return it has escaped after eating their food and is next seen fully grown.** Similarly, in the sequel the there are dozens of fully grown aliens (and a ''very'' fully grown queen) along with a giant organic maze in the terraforming facility, despite the fact that there are only some 150 humans to eat. Bishop mentions that the colonists also had livestock, which could serve as hosts/food for the aliens.** It's proposed in an in-universe anatomical/zoological report on the xenomorphs (in the Dark Horse comic series) that the reason for their blood being acidic is that it is in fact a living battery (which would kinda work, seeing as how they're silicon-based lifeforms), and that they get all the energy needed for their (individually) relatively short lifespans as an adult from this as well as from their host organism and thus do not actually need to feed, nor do they even have digestive systems. This is similar to a lot of butterfly and moth species in real life (the thing with adults not eating... not the thing with bursting out of people's chests(!)), though they emerge from their cocoon as fully-grown adults, while the xenomorphs emerge from their living cocoons as infants, so just how biologically feasible this might actually be is debatable. Additionally, like bees, the Queens feed off of "royal jelly", a substance which (in-universe) is shown to have phenomenal medicinal and performance-boosting properties in humans.* AsceticAesthetic: {{Deconstructed}} in several ways. The ''Nostromo'' in the first film, for instance, clearly had this look before the wear and tear set in. The colony in the second film, meanwhile, has a facade of this look over a greasy industrial substructure. The contrast between this trope, UsedFuture, and unsettling organic structures is a recurring theme throughout the franchise.* AttackAnimal: WordOfGod states that the Xenomorphs are these.* BetterToDieThanBeKilled: Subverted in the ''Newt's Tale'' comic series. During the colonist's final stand against the xenomorphs, Newt's mother picks up a gun and looks at her children (intending to put them out of their misery before turning the gun on herself). She gets ready to pull the trigger...and then Newt tells her there's another way, and leads them towards a ventilation grate during the attack. Not that it helps, considering that her mother and brother get ripped apart seconds later, forcing her to flee into the duct.* BewareMyStingerTail: Even if the "sting" was not used, the xenomorphs on film still demonstrate this by using their bladed tails as a weapon, often [[ImpaledWithExtremePrejudice impaling a victim on them]].* {{BFG}}: The combination gun Ripley is carrying at the end of Part 2 in the Dark Horse comic of ''Aliens'' has to be seen to be believed.* BizarreAlienBiology: Extremely so, and possibly one of the most famous examples.* BloodyMurder: Acid blooded aliens.* BodyHorror: The aliens' parasitical breeding cycle turns you into a living incubator. Cf. certain species of wasp. Nature even on Earth is not always cuddly and fluffy.* BrokenBird: [[spoiler:Newt AKA Billie]] is one in the Dark Horse comic series.* BugWar: A small scale version. The first and third films center on a group of human noncombatants against a single alien, while the second and fourth films feature groups of armed people against a horde of aliens. The ''Franchise/AlienVsPredator'' series features a full scale battle between the species in the second movie. The "war" part didn't happened until ''Aliens versus Predator 2''.* CanonDiscontinuity: ** The Dark Horse comics totally ignore ''3'' and ''Resurrection'' because they were written before ''Alien 3'' came along and killed everyone. In the novelizations, Newt and Hicks were replaced by [[{{Expy}} Billie and Wilks]] and Ripley was [[spoiler:revealed to be a artificial person with implanted memories]].** The ''Out of the Shadows'' trilogy serves as a ContinuityReboot for the expanded universe, disregarding the comics and other novels, aside from a few MythologyGags. The second book very nearly decanonized ''3'' and ''Resurrection'' as well, before Fox changed their mind and asked the author to include references to them.** Neil Blompkamp's film was suggested to ignore ''3'' (and ''Resurrection'' by extension) due to early concept art featuring an older version of Newt, who [[DroppedABridgeOnHim had a bridge dropped upon her]] in the opening of that film.[[note]]Hicks was revealed to have survived in ''VideoGame/AliensColonialMarines''.[[/note]] Blomkamp clarified that [[http://www.blastr.com/2015-3-2/why-neill-blomkamp-says-hes-not-trying-undo-alien-3-and-alien-resurrection his film would not be retconning them]], while Sigourney Weaver [[http://www.indiewire.com/2016/07/sigourney-weaver-neill-blomkamp-alien-sequel-continuity-1201703361/ indicated it would be set in]] an AlternateTimeline.* CaptainErsatz: The two main characters in the first two arcs of the comic series were Newt and Hicks. When ''Alien 3'' killed the characters off, future printings of the comic [[RetCon changed their names to Billie and Wilks]], though this seems an odd choice in retrospect, as their backstories remained identical and the comics had diverged so sharply from the movies by that point that keeping them in step with one another seems irrelevant.* CeilingCling: With instances of VerticalKidnapping.* CocaPepsiInc: As everybody knows, Weyland-Yutani is a combination of rival motoring conglomerates British Leyland and Toyota.* ColdSleepColdFuture: The world seems to get a little bit grimmer each time Ripley wakes up. In the first film, the Company is willing to risk the lives of a ship's crew to get its hands on an alien. In the second film, the Company (or at least Burke) is willing to sacrifice a whole colony to breed aliens. In the third film, Ripley wakes up on a planet that is inhabited solely by a prison. In the fourth film, the megacorporations have given way to an even more irresponsible military that actually goes through with alien genetic testing. The comic book canon is [[CrapsackWorld far worse than even this.]]* ConservationOfNinjutsu: Occasionally (some deleted scenes in ''Aliens'', the flashback in ''Alien Versus Predator'' and many times in ''Film/AliensVsPredatorRequiem''), the Aliens abandon their stealth kill tactics for a ZergRush, which goes about as well for them as one might expect. It actually works pretty well in the first AVP film...[[spoiler:until the Predator SelfDestructMechanism kicks in.]]* ContinuousDecompression: Used in Part 1 and 2 during the ThrownOutTheAirlock scenes. Part 4 has incredibly big aliens blown out of incredibly small holes. * ContinuityReboot: The ''Fire and Stone'' comic series and the ''Out of the Shadows'' trilogy of novels serve as a reboot to the ''Alien'' and ''AVP'' franchises' expanded universes, while containing {{Continuity Nod}}s to earlier entries. * CorruptCorporateExecutive: This is evidently humanity's [[PlanetOfHats hat]] in the Alien universe.--> '''Ripley:''' You know, Burke, I don't know which species is worse. You don't see them fucking each other over for a goddamn percentage.* CrapsackWorld: The Dark Horse comic series is one hellish place to live. The MegaCorp controls the world, all civil rights are essentially gone, the military kills civilians with impunity, and that's before the two killer alien species come knocking. The Aliens overrun Earth and more than one character wonders if we deserved it.* {{Crossover}}: ** Famously so with the Predators in ''Franchise/AlienVsPredator''.** A Xenomorph appears as a GuestFighter in ''VideoGame/MortalKombatX'', born out of the MK-specific Tarkata race. Coincidentally, a Predator also appears as a playable character, tying in with the above.* CreepyLongFingers: Most designs for the aliens give the extraterrestrial monsters long, clawed fingers. Some go so far as to make them more than a foot long.* DominantSpeciesGenes: When Aliens implant themselves into other species, the result is obviously a xenomorph (black skin, spiked tail, huge head, Nested Mouth..) but it has slightly different characteristics depending on the species that was implanted (a dog gives a four-legged version instead of the usual type, a Predator has mandibles, etc.).* DroolHello: The movies are pretty fond of this one. Whenever dripping saliva onto the victim won't signal a Xenomorph's presence, the warm air exhaled onto the victim's neck from behind will. And if that happens, it's already too late to run.* DwindlingParty: Across the films, if you see a main group of characters, expect only one or two survivors in the end* EmpoweredBadassNormal: Ellen Ripley was a normal human who TookALevelInBadass by the end of ''Film/{{Aliens}}'' by destroying an entire alien hive by herself, fighting against acid-bleeding parasitic Xenomorphs. Then by ''Film/AlienResurrection'' her clone Ripley 8, who shares most of her memories, receives some Alien DNA as a result of a flaw in the cloning process. Ripley's own blood becomes slightly acidic, she gets a psychic connection with the Xenos, has reduced empathy and predatory instincts, and is able to [[MadeOfIron shrug off being hit in the face with a loaded barbell]].* EnemyDetectingRadar: The motion trackers from ''Aliens'', which often appeared in video game adaptations of the franchise.* EverybodysDeadDave: In the comic series ''Aliens: Newt's Tale'', [[spoiler:Newt is the only one to survive the colonists' last stand at LV-426, and is forced to go into hiding and foraging by herself after watching her mother and brother get massacred by the xenomorphs right in front of her.]]* EverythingTryingToKillYou: In the comics, a group of Marines is forced to go to the Aliens' homeworld to act as bait for facehuggers. One character sagely notes that, on other worlds, the Alien is a foreign creature which the locals are not used to dealing with. On its own planet it would have struck an ecological balance with other species, and it ''might not even be the dominant predator.'' The bait plan is completely misguided because unbeknownst even to themselves, [[spoiler:all the Marines are androids.]]* EvilIsVisceral: In addition to creating many of the subtropes, the alien eggs and the visual design of the Space Jockey are also this.* EvolutionaryRetCon: The xenomorphs from the later films are much more insectile and predatory than [[Film/{{Alien}} the original film]]'s man in a suit version.* ExcessiveSteamSyndrome: Numerous examples across the entire main series and {{Crossover}} films. This includes the Nostromo, the Sulaco (in the third film as the alarms are triggered), the Auriga, the Betty and even the downed Predator ship from ''Requiem''.* EyelessFace: The most distinctive trait of the Aliens other than...* FaceFullOfAlienWingWong: The Xenomorphs' horrifying life cycle starts with this.* FateWorseThanDeath: Giving "birth" to a Chestburster. This is highlighted by the iconic plea, "Kill... me!" spoken by impregnated alien victims. * FetusTerrible: Chestbursters are parasites intended to evoke this.* FourTemperamentEnsemble: The films themselves are an odd non-character example in terms of their respective tones and atmospheres (and even in light of the personalities and resumes of their respective directors): ''Film/{{Alien}}'' is phlegmatic, ''Film/{{Aliens}}'' is choleric, ''[[Film/{{Alien 3}} Alien³]]'' is melancholic and ''Film/AlienResurrection'' is sanguine.* GaiasLament: Earth in the series. It has become an overpolluted slum.* GenreBlindness: Of all people, the CEO of Weyland-Yutani themselves. In their mad obsession to acquire the Xenomorph, they seem to keep forgetting that sending a bunch of "expendables" who are out of the loop to inadvertently bring the alien back to Earth and planting a mole in the team ''always'' backfires on them when the protagonists inevitably figure out they were set up and then kill the aliens themselves. ** Though, it looks to have finally succeeded in Aliens: Colonial Marines.* GenreShift: The first movie is "a haunted house in space'' while the second is intended to be "the Vietnam War in space." The third went back to being a sci-fi horror film while the fourth went back to being a sci-fi action film.* GoodLipsEvilJaws: The Aliens.[[/folder]]

[[folder:H-M]]* {{Hermaphrodite}}: The titular aliens themselves, at least according to H.R Giger.* HiddenInPlainSight: See, this is the problem with living in a dark UsedFuture with monsters after you. In ''Alien'', the Alien stows itself in the wall paneling; in ''Aliens'', several Aliens are curled up in alcoves on the wall in the hive, perfectly blending in with the walls. They are even invisible on IR due to the pervasive heat.* HissBeforeFleeing* HiveCasteSystem: The series features several stages of life for Xenomorphs, from facehuggers through chestbursters to your standard double-jawed Giger nightmare. And then there was the Queen, who laid eggs and was [[MamaBear fiercely protective of her offspring]]. It was implied and then later confirmed in the movies, video games and books that the xenomorphs take on characteristics from the host they gestate within. That explains why a chestbuster coming from a dog looks doglike and why one from a ''Franchise/{{Predator}}'' is bigger than those from humans and has the characteristic mandibles and dreadlocks.* HollywoodAcid: Xenomorph blood easily chews through ship decks, industrial steel floor grates, and body armor. Never mind what it can do to flesh. Notable in that its potency freaks ''everyone'' out; one character makes noises about "[[TechnoBabble molecular acid]]" in the first film, and an executive speaks of "concentrated acid" in a patronizing manner in the second - they're basically saying, "Umm... Acid '''isn't''' supposed to '''''do''''' that!"* HornyDevils: Giger designed the aliens to embody the fear of rape. The face-huggers essentially rape their victims and impregnate them. In the first film, it's implied that an adult alien sodomizes Lambert with its tail.* HumansAdvanceSwiftly: If you count the film ''Film/{{Prometheus}}'' in, you may notice how the robots' personalities are becoming more human as the in-universe timeline moves on. * HumansAreTheRealMonsters: In all the films except for ''Alien³'', the Aliens are set loose due to human greed mixed with incompetence. Even in the third movie however the only reason the Company sends a rescue mission to Fiorina-161 is because they suspect [[spoiler:Ripley is carrying a Xenomorph embryo.]] Otherwise they'd basically abandoned their HellholePrison planet because it was unprofitable.-->'''Ripley 8''' (regarding [[spoiler:Analee Call]] revealing herself as an android in ''Resurrection''): I should have known. No human being is that ''humane''.* ICannotSelfTerminate: Any given character with a Alien fetus inside them: "Kill me... kill me..." Justified as usually the victim is cocooned and immobile, otherwise they'd surely do the job themselves.* ImpaledWithExtremePrejudice: Happens a few times, what with the Aliens having bladed tails. * ItCanThink: The aliens are revealed to be intelligent in the series. See the film pages for more details.* JustFollowingOrders: Ash in the first movie, and possibly Burke in the second movie (it's never clear whether he's operating on orders from the Company or he's in it for himself). David in ''Prometheus'' may count as well, although [[AIIsACrapshoot he may have let his feelings get in the way]] ''just a little''.* KillItWithFire: Want to survive fighting the aliens in close quarters? Flamethrowers are the only way to avoid being hit with their acidic blood at close range.* LargeAndInCharge: The Xenomorph foot soldiers or "drones" are already significantly larger than their hosts (usually humans), but the Queen Xenomorph who creates all the others is about the size of a ''T. Rex''.* LegoGenetics: The Xenomorphs, as part of their bioweapon design, can assimilate useful traits from their hosts to better survive in the environment and become stronger, and it often extends to physical appearance. The first two films had human-like Xenos, and the third featured a quadruped Xeno that came from a dog (or a bovine, depending on the version). The video games, comics and toy line take it to greater lengths with flying Xenos with wings like a bird or bat (an alien Queen that burst out of ComicBook/{{Vampirella}}), gorilla Xenos with long powerful arms, bull and rhinoceros Xenos, and in the Franchise/{{Batman}} crossover comics the Xenomorphs even had physical similarities to the various villains their DNA was combined with (with the Killer Croc Alien being a gigantic crocodile-like beast). And the most iconic type, the Predalien, a Xenomorph born from a Predator with a shorter skull, mandibles, dreadlocks, and a stockier build than other humanoid Xenos. Interestingly, with few exceptions, the Queen Aliens and other higher castes like the Praetorian do not assimilate traits, keeping the Xenomorph line pure-blooded.* MadScientist: ''Quite'' a few in the comics, perhaps most notably [[FourEyesZeroSoul Church]] from ''Labyrinth''.* MainliningTheMonster: Aliens produce Royal Jelly which has the same role for this species as it has for real-life bees. However, it is also an extremely valuable substance in human society, used as a powerful and mind-enhancing drug for wealthy individuals. Since the only source of Royal Jelly is often deep inside an alien hive, collecting it can be very dangerous. The ''Hive'' mini-series details such an operation.* MegaCorp: Weyland-Yutani is the very epitome of this trope. They control every Earth government and have colonized many star systems. Not only that, but they have a private army with a bioweapons division. They have prison planets as well, such as the one in the third movie. The fourth movie changes this up by referring to megacorps like Weyland-Yutani as a thing of the past, though the government that replaces them is just as bad, if not worse.* MercyKill: Often requested by victims. Usually granted, if the opportunity is there.* MetamorphosisMonster: The Aliens go from parasite to two-legged horror.* MonsterIsAMommy: The Alien Queens.* MoreTeethThanTheOsmondFamily: The titular Aliens.* MustHaveCaffeine: The singular common vice shared by ''every'' adult-character with spoken lines of dialogue in this franchise, to accentuate how this is a story about "Blue Collar Working Nine To Five Joes and Janes."[[/folder]]

[[folder:N-S]]* NestedMouths: The Aliens. Probably the most iconic case.* NonhumansLackAttributes: The Xenomorphs have no genitalia. ''We hope''.* OddlyNamedSequel2ElectricBoogaloo: You can see there's no consistency on the naming (which is why it's one of WebVideo/TheAngryVideoGameNerd's targets [[http://www.youtube.com/watch?v=OEVzPCY2T-g here]]).* OneGenderRace[=/=]MonogenderMonsters: Xenomorphs are canonicaly all-female. One deleted scene showed that the average drone can lay eggs when separated from the Hive.* OutgrownSuchSillySuperstitions: Averted. The first two films are silent about religion, but ** In ''[[Film/{{Alien3}} Alien³]]'' the inmates of the prison colony have got religion. ** In ''Film/AlienResurrection'' the space station has a chapel, and one character makes the Sign of the Cross upon entering, which is a typically Catholic observance and a somewhat old-fashioned one at that. This character is later revealed to be an android, and there is a mention of androids investigating religion for a morality which is chosen, rather than imposed through programming. ** In ''Film/{{Prometheus}}'', Elizabeth Shaw is a Christian. Not much is made of this, but she clearly keeps her faith - her last act is to give the date, in the style "year of Our Lord." * {{Phlegmings}}: Every time the aliens appear.* TheQuest: An evil corporate one at that; almost all of the films and most of the related media include references to Weyland-Yutani's attempts to acquire at any cost at least one of the Aliens.* RecursiveCreators: In ''Prometheus'' and ''Alien: Covenant'', the different species in the overall franchise are established to each be engineered by a preceding one. The known order is Engineers creating Humans, then Humans creating Androids, then Androids creating Xenomorphs.* RightManInTheWrongPlace: Ripley, particularly in the second film.* RoboticReveal: When someone starts leaking milk-colored SymbolicBlood, you've got one of these.* RuleOfScary: There are plenty of rationalizations of the xenomorph's life cycle, the circumstances, and behavior of various characters, but in the end it all comes down to this.* SculptedPhysique: The Alien, which is not surprising considering artist Creator/HRGiger's other works. This use of the trope actually makes sense production wise since the alien's black and tube-like exterior made it blend in on the spacecraft. This is so effective in the first film, that the first time we see the adult Alien, it's ''hanging in full view of the camera'' and you probably mistook it for piping![[note]]For the curious, it's the scene where one crewman goes after the cat and he looks upwards at the chains hanging from the ceiling. See the metallic looking bundle in the bottom right? There's the cowboy![[/note]]* SequelEscalation: ''Alien'' has a single xenomorph preying on civilians. ''Aliens'' has a full colony of bugs pitted against a platoon of Space Marines. The third movie reverts back to the original scenario. The fourth movie escalates it to a whole hive of Aliens again.* SiliconBasedLife: Xenomorphs are apparently silicon based.* SleeperStarship: FTL travel apparently takes months so they use cryo.* SmokingIsCool: Aside from the vice of MustHaveCaffeine, ''every'' single '''heroic''' adult character (well, aside from the DirtyCoward Lambert) with spoken lines in the Alien Franchise is bound to smoke a pack of cigarettes a day like a chimney.* SoleSurvivor: Newt in the ''Newt's Tale'' comic series* SpaceClothes: Averted. The crew members wear normal clothes. People entering cryogenic sleep strip down to their underwear; otherwise, they usually walk around in civilian/military attire. In the opening scene of ''Alien'', the clothes are distinctly reminiscent of diapers, as the lethargic crew are "born" from closed spaces into the white room controlled by the AI "Mother".* SpaceIsNoisy: There are some flight-cruising sounds, and in the fourth one, an [[StuffBlowingUp explosion.]]* SpaceMarine: A platoon of Colonial Marines is dispatched to [[SendInTheSearchTeam investigate a human colony that has gone silent]]. They find a xenomorph hive and are largely wiped out, [[MutualKill destroying the hive and killing the Queen in turn.]]* StarfishAliens: The Aliens.* SuspiciouslyStealthyPredator: The xenomorphs. They nest in warm, humid places which help mask their infrared profile, their bodies blend in well with darkness and pipes, and they can remain completely motionless. It is almost as though they are perfectly adapted to concealing themselves in an obviously artificial environment. * SymbolicBlood: Androids have white blood and organs. Naturally, both the android in the first film and Bishop get torn apart so it sprays everywhere. In ''Alien'', the insides of the android were made from milk, pasta, and glass marbles. Apparently Lance Henriksen [[http://www.imdb.com/title/tt0090605/trivia?tr0794428 got food poisoning]] from said milky blood while shooting that scene.[[/folder]]

[[folder:T-Z]]* TertiarySexualCharacteristics: The Queen Alien's feet are shaped like high-heeled shoes.* ThemeNaming: Each synthetic character has a name from the first three letters of the alphabet, in accordance with their order of appearance: [[spoiler:'''A'''sh, '''B'''ishop and '''C'''all]]. ''Film/{{Prometheus}}'' continues this trend with '''D'''avid.* TookALevelInBadass: Ripley's mutation from being a scientist to a badass alien killer is a running theme through the franchise.* TrappedWithMonsterPlot: The first film is one of the most famous examples, and almost every entry in the franchise is also an example.* TropeCodifier: The series as a whole is this for UsedFuture, along with ''Franchise/StarWars'' (which Cameron cites as a direct inspiration). ''Aliens'' in particular defined the StandardHumanSpaceship visual style for humans and their [[OurWeaponsWillBeBoxyInTheFuture military tech]] in a StandardSciFiSetting. ''Series/BabylonFive'', ''VideoGame/FreeSpace'', ''VideoGame/StarCraft'', ''Franchise/{{Halo}}'', and ''Franchise/MassEffect'' (to name a few) all draw on it. ** In a case of a work codifying tropes for an entirely different medium, the films cemented a number of formulae embraced by FirstPersonShooters and ThirdPersonShooters several years after the second film. The gun-floating-on-the-bottom-of-the-screen POVCam and target-centered OverTheShoulder shots from the Marine gunner's incursion and Ripley's final assault on the hive, for instance, are prototypes for the standard screen layouts of both genres, as well as the cramped hallway sieges that defined the early days of 3d shooters. The gunner's flashy heavy weaponry, the grenade launcher on the assault rifles, and Ripley's kludged-together multi-firearm, meanwhile, together established a precedent that ensured the future prominence of tropes like GatlingGood, SwissArmyGun, SecondaryFire, WalkingArmory, and the {{BFG}}.* UnitedSpaceOfAmerica: it's all but explicitly stated that the US is still a superpower centuries in the future, complete with its own colonies. Also, the Colonial Marines are clearly shown as American.* UsedFuture: The first film in particular is a notable early example: the cold, underlit grungy ship ''looks'' like a run-down refinery ship. It's a big break from the sparkly white corridors and spandex jumpsuits.* VerticalKidnapping: The Aliens are fond of doing this. Famous last words include "Maybe they don't show up on infrared at all..." and "This is rumor control, here are the FACTS."* VillainBall: In the Dark Horse comic, a Company plant (and a psychopath) kills an officer to prove to his hostages how ruthless he is, while said officer is attempting to flat-out tell him that his plan to infect the marines will not work [[spoiler: because they are all androids]].* VillainBasedFranchise: The franchise in general is this, but not the movie series due to centering on Ripley.* WhyIsntItAttacking: Quoted almost word for word by one of the Android Marines in the Dark Horse comic. This was the first major indicator that the marines were not what they believed themselves to be.* XenoNucleicAcid: The Xenomorphs have what's called a "DNA Reflex," which is apparently why they end up looking similar to their host species. This is further elaborated on in novels and guides, such as The Weyland-Yutani Report. The Chestburster functions much like a cancer, being built from the body's own cells and integrating 10-15% of its DNA in order to prevent an immune response. This causes the Xenomorph to develop similar physical traits, possibly mental ones as well, such as a specific gait or physical features. The reverse is also true; the host has some of the Xenomorph's genetic material integrated into its body during the Chestburster's incubation.* YouAreInCommandNow: In the Dark Horse comic series, at least at one point, it's ''Newt's'' turn to step up to the plate.* YouKeepUsingThatWord: The Alien "Quadrilogy" DVD set. They invented that word for marketing purposes. It would actually be called a [[http://en.wikipedia.org/wiki/Tetralogy Tetralogy]].* {{Zeerust}}: Spaceship electronics are based on bulky 1970s computers like the Apple II series which were considered cutting-edge at their time.* ZombieInfectee: Most people who know they're incubated by an Alien Facehugger, and its effects, choose to bite the bullet or die in a HeroicSacrifice. One memorable scene from ''Alien: Resurrection'' involved an infectee bear-hugging the scientist responsible for his infection, forcing the Chestburster to go through his chest ''and'' the scientist's '''head''', [[TakingYouWithMe taking his murderer with him to the afterlife]]. This was actually done in the comic, many years before, but the artists had the creature enter the researcher's chest.[[/folder]]----